1. Technical Field
Example embodiments relate to an audio amplifier, and more particularly to an audio amplifier that compensates a DC offset included in an output signal thereof.
2. Description of the Related Art
An audio amplifier is widely used to amplify an input audio signal to provide an amplified output audio signal for driving a load such as a speaker. Generally, the audio amplifier may be categorized into a class-A amplifier, a class-B amplifier, a class-AB amplifier and a class-D amplifier. The class-A, class-B and class-AB amplifiers may be used in an analog system and the class-D amplifier may be used in a digital system.
The class-A amplifier is used for amplifying a small signal, but has relatively low efficiency. The class-B amplifier has higher efficiency than the class-A amplifier, but has low linearity characteristic due to crossover distortion. The class-AB amplifier has higher efficiency than the class-A amplifier and higher linearity characteristic than the class-B amplifier, but has lower efficiency than the class-D amplifier. The class-D amplifier has relatively high efficiency that is typically more than 80% at maximum output. In addition, the class-D amplifier may be implemented in a silicon chip with a small size as well as low cost. Accordingly, the class-D amplifier may be widely used in low power applications, particularly mobile devices, which are required to be miniaturized with low power consumption.